[SeanWRT]

Updated on Apr 28, 2017 - The drone is gone forever. Today I just realized, it's been a couple weeks I didn't hear drone. Tried hard to look for it, it's nowhere to be found. Kind of miss it...

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HJS Euro 6 Downpipe was installed at Christmas of 2016. The thing really turns up everything in a pleasant manner without compromising anything whatsoever from stock. Truly a mod that you'll be appreciating and never get tired of for the length of car ownership.
See my review here:
http://f87.bimmerpost.com/forums/sho....php?t=1339166

MPE, on the other hand, is deemed by its maker illegal in its purest form. An amazing sounding system few six pots can match, I'll give it that. But it comes with imperfections which you'll have to live with. Out of spending one week with it, I make a list of my findings:

1) Drone - My prayer wasn't answered. Didn't get away with that. It drones the day of install from 2500~4000 under heavy load, though things were getting better pretty quick - the range gets narrower to 3000~3500 as of today and volume decreased already to an acceptable level. Sport mode was even slightly better. From time to time the drone seems little to almost gone even in track mode but that's inconsistent. Out of drone range it's sounding nothing but spectacular. I am expecting it self cures over time. Already ordered ASD bypass hoping it works. I will update.

2) Startup Vibration - Yes it vibrates, which I anticipated and had addressed. Result is no noises can be heard or a negligible one if you stand behind and look for it, not an issue at all.
Two measures:
a) Tighten up tailpipes screws harder than installation manual suggests - it's the source of noise.
b) Weld up pipes and clamping bush - one piece is less prone to vibration.
BTW, forum members here reported a two-time vibrations at cold start but my car only vibrates once and for a short time (3 secs or so) - I guess it's the welding of pipes/bush that neutralizes one of them and lessen the other.

3) Unlike a downpipe amplifying stock sounding, MPE is much of a differently tuned system. In higher rpms where stock gets muffled a little bit, MPE opens it up with rawness. At down low and in between, MPE presents more clarity while stock system goes deep. Those characteristics are very prominent in track mode, making an acoustical pleasure all the time on the road.

4) On loudness. I'll confess, yesterday I activated track mode and unplugged the BT control module. That's how it stays in track, permanently. I did it because of what's said in #5 below. Remind you, I consider myself a conservative guy in judging how loud is too loud, track is not too loud. And that is said with high flow downpipe fitted, especially when you have stock comfort in place and are staying below 3krpm where F87 has plenty of torque already for normal use unless you want Tesla's push which m2 is not able to give anyway. In this sense, I have no idea how people who cannot live with track mode day to day bought a MPE in the first place.

5) Compared to stock system, MPE in Sport mode is slightly louder at middle & top end, at cost of down low deepness from stock that everybody absolutely loves. You'll feel it the most the sec engine's lighted up in MPE sport - the sexy deep breath is gone. The track mode, however, makes a day and night difference, it wakes up in a mighty roar with burbles and crackles, which is definitely more exotic and attention drawing. But from the bottom of my heart, I still miss the refinement that only stock system can give.

6) A trivial thing - there is very slight sound "shoooo" from exhaust when window down (please hear it from the video, from 13~17 sec). It sounds like the pipe is sucking/blowing air or something (or leak?). It's there when you look for it and more noticeable in the garage. Is anyone out there experiencing the same?

In summary, with all those imperfections, HJS & MPE combination captures a perfect balance among all dimensions and IMO is "the system to beat". I heard many, if not all, different systems for F8X, most of them cannot make low end charm without being raspy at top end, you can easily tell in few rev-ups that they're simply much less refined. In my 30 ///M meet last weekend, many F8Xs came with much louder systems, but there was a general consensus that my car claimed the crown and blew away every single one of them.

Check out the sound clip.

First half is all about burbles and crackles when lifting off at below 4500k, the other half is me redlining it. Though for sure high revving would be even much better on the fly.

[auf Deutsch]

Is the drone from the DP or MPE?

[M2wolf]

Sounds exciting. I'm pondering to opt for a fabspeed or hjs combing with the mpe.

[TheDutch]

Sounds good with the dowpipe. Quick Q: how did you 'unplug' the BT to let the valves stay open?

[LBBDrew]

SeanWRT did you install the DP after the MPE? (were you able to judge the MPE independently before installing the DP?) Curious as to how much volume as added with the DP on top of the exhaust

[SeanWRT]

Originally Posted by auf Deutsch

Is the drone from the DP or MPE?

Many talk about drone, few really understand it. Drone is the phenomenon where cabin resonate to exhaust flow at specific frequencies, as a result in-cabin sound, as a vibrating system, oscillates with greater amplitude, which means more noise to be heard.

High flow downpipe does not alter frequencies but only amplify, or restrict less than stock, whatever comes out of exhaust manifold. If it drones to begin with, DP makes it drone louder. If it doesn't, DP will not make it do.

Originally Posted by M2wolf

Sounds exciting. I'm pondering to opt for a fabspeed or hjs combing with the mpe.

You'll be getting a similar sounding system with Fabspeed, only a little bit louder.

Originally Posted by TheDutch

Sounds good with the dowpipe. Quick Q: how did you 'unplug' the BT to let the valves stay open?

1) Put it into Track Mode via BT remote controller
2) Disconnect module-to-battery wire from battery end under trunk liner.

Be noted, press the button on the module (the one in the trunk) will NOT do it - I thought it would, only to find out valve closes itself immediately when I did that.

Originally Posted by LBBDrew

SeanWRT did you install the DP after the MPE? (were you able to judge the MPE independently before installing the DP?) Curious as to how much volume as added with the DP on top of the exhaust

I love you guys, but I am not going to remove DP and put back stock catback and do the comparison...My impression is 20% louder from DP and on top of that, 20% increase from MPE in track across the band or 10% from in sport at top end. I think you'll be safe taking those numbers. As said earlier, DP amplifies sounds by a pretty consistent margin in %.

A side note: the drone completely was gone today in my 20 minute commute to office...just like what's mentioned in OP its presence is inconsistent. But things seem forwarding in good direction.

[mike@x-ph.com]

Originally Posted by M2wolf

Sounds exciting. I'm pondering to opt for a fabspeed or hjs combing with the mpe.

Do it!

[mike@x-ph.com]

Thank you for the review OP

[Orange fever]

Thanks for the vid, time to save up for it ///

[Fab_R]

Great honest review...thank you.

What is it like with valves closed and lower range rpm?

Basically want to know when just trundling around, is it like the stock exhaust?

And in MDM valves open....?

[SeanWRT]

Originally Posted by Fab_R

Great honest review...thank you.

What is it like with valves closed and lower range rpm?

Basically want to know when just trundling around, is it like the stock exhaust?

And in MDM valves open....?

MPE in sport with Comfort, the mode combo where both factory and mpe valves are closed, sounds close to stock system at down low in term of volume, but isn't as deep.

MPE in track with Comfort (left valve closed but right one open), is louder and clearer and makes sightly more burbles, better than stock overall, but it also costs you a little bit deepness.

In MDM, either sport or track it burbles like crazy.

[Fab_R]

Originally Posted by SeanWRT

MPE in sport with Comfort, the mode combo where both factory and mpe valves are closed, sounds close to stock system at down low in term of volume, but isn't as deep.

MPE in track with Comfort (left valve closed but right one open), is louder and clearer and makes sightly more burbles, better than stock overall, but it also costs you a little bit deepness.

In MDM, either sport or track it burbles like crazy.

Awesome... Thanks for answering.

[TheDutch]

Originally Posted by SeanWRT

1) Put it into Track Mode via BT remote controller
2) Disconnect module-to-battery wire from battery end under trunk liner.

Be noted, press the button on the module (the one in the trunk) will NOT do it - I thought it would, only to find out valve closes itself immediately when I did that.

Thanks! Gone for the same route now, HJS + MPE w/ valve open + Eventuri

[AGM2]

Sound great !!

[SeanWRT]

Update:

I remove the ASD last week. It's got quieter overall, but in cabin sound quality improves, especially at down low - there is no fake engine load noise on top of real one when you're just being gentle on gas below 2000 rpm, not in the mood for noise. On the other hand, you hear more from exhaust, which is purer and more raw. Downside is at higher rpm, high pitch may be lost a little bit (or it's just all in my mind as difference is minimal I can't tell for sure). I really like it for what it actually is. In summary it's definitely the right thing to do.

It's been 2 months and drone is still present though minimal and sometimes gone completely. I think I must be out of my mind to say this: I love the drone and kind of look forward to that little noise when revving it up...

Having compared many enough F87 sounding systems in real life, I am very confident coming to this conclusion - MPE+DP is THE BEST setup BY FAR. I must have many crazy friends tolerating nothing but the very best - three sets of this below were ditched in mint condition in past 2 months because of what's heard side by side in comparison.

[M2GB]

Originally Posted by SeanWRT

MPE in sport with Comfort, the mode combo where both factory and mpe valves are closed, sounds close to stock system at down low in term of volume, but isn't as deep.

MPE in track with Comfort (left valve closed but right one open), is louder and clearer and makes sightly more burbles, better than stock overall, but it also costs you a little bit deepness.

In MDM, either sport or track it burbles like crazy.

Is MPE in track mode bypassing the muffler altogether?

[SeanWRT]

Originally Posted by M2GB

Is MPE in track mode bypassing the muffler altogether?

This should explain it well. Left side is the stock valve and right side is MPE valve.

Either in track or sport, flow partially goes into muffler, to different extent is all.

[SeanWRT]

Just to update you guys - the drone is gone forever. Today I just realized, it's been a couple weeks I didn't hear drone. Tried hard to look for it, it's nowhere to be found. Kind of miss it...

[AndrewC1989]

Originally Posted by SeanWRT

6) A trivial thing - there is very slight sound "shoooo" from exhaust when window down (please hear it from the video, from 13~17 sec). It sounds like the pipe is sucking/blowing air or something (or leak?). It's there when you look for it and more noticeable in the garage. Is anyone out there experiencing the same?

That's completely normal and it's because of your sportcat. My 200Cell fabspeed sport cat made my car do the same. It's the sound of the turbo unspooling. i absolutely love that noise.

Thanks for posting your honest and detailed review. I love all of the high range snaps and crackles but like you said, the low deep tones are gone. This is my cars sound at the moment. I'm trying to decide if MPE is the route i'd like to go or if i should take another route. here's how it sounds now:

[JL1]

Originally Posted by SeanWRT

Update:

I remove the ASD last week. It's got quieter overall, but in cabin sound quality improves, especially at down low - there is no fake engine load noise on top of real one when you're just being gentle on gas below 2000 rpm, not in the mood for noise. On the other hand, you hear more from exhaust, which is purer and more raw. Downside is at higher rpm, high pitch may be lost a little bit (or it's just all in my mind as difference is minimal I can't tell for sure). I really like it for what it actually is. In summary it's definitely the right thing to do.

It's been 2 months and drone is still present though minimal and sometimes gone completely. I think I must be out of my mind to say this: I love the drone and kind of look forward to that little noise when revving it up...

Having compared many enough F87 sounding systems in real life, I am very confident coming to this conclusion - MPE+DP is THE BEST setup BY FAR. I must have many crazy friends tolerating nothing but the very best - three sets of this below were ditched in mint condition in past 2 months because of what's heard side by side in comparison.

Hey Mate,

Have you heard the Remus cat back in real life? and how does it sound compared to your car if you have? heaps of people are saying value for money the remus is one of the best exhausts and is of high european quality?

[SeanWRT]

Originally Posted by JL1

Hey Mate,

Have you heard the Remus cat back in real life? and how does it sound compared to your car if you have? heaps of people are saying value for money the remus is one of the best exhausts and is of high european quality?

Hi JL1, there's no local m2 using Remus that I'm aware of. Although I heard great things about Remus as an exhaust system brand.

[Aisxos]

Thank you for the perfect review...
I was ready to order akrapovic but i will trust you and order your setup..